Every ArmadilloCon has a world-building panel. It’s one of those panels that can be done a million times and still remain fresh. With different panelists it can be very different each time. This time the panelists were James P. Hogan, Elizabeth Moon, Julie Czerneda, Paul Benjamin, and Mikal Trimm.
The world creation process was anything but logical. It was based on loose associations and wordplay. It was 10 pm on a Saturday night, and many panelists might not have been up to anything more rigorous.
In the beginning, Elizabeth Moon surveys the audience with a critical eye and asks Julie Czerneda how many people in the audience she thinks they could use in their plot. (The plot of a hypothetical book set in the universe they are building.) Moon tells the audience they’ll need to grow tentacles.
Julie Czerneda creates worlds for a living. It has to do with the fact that she writes novels with very different alien civilizations in them. She shows the audience a copy of her new book that’s going into the charity auction, and the copy is special in that it has two endings. The alternate ending is put in a white envelope and included in the book. Only the lucky auction winner will have a chance to know the alternate ending.
The panelists divide the audience among themselves. The left row will be James Hogan’s universe, the middle row will be Elizabeth Moon and Julie Czerneda’s universe, and the right row will be Mikal Trimm’s and Paul Benjamin’s universe. Then they make a guy in the audience volunteer for an editor’s job. The editor is told to sit in a separate chair to the side of the stage, and is assigned a veto power. If he sees something that doesn’t make sense with the universe, he’ll be able to veto it.
First, Elizabeth Moon asks each group to determine whether their universe is going to be expanding, contracting, or stable-state. The groups make their decisions, but, as we see further, it makes no difference, because their universes follow not the laws of physics but the laws of humor. Then Moon asks to decide what kinds of stars will they have. Mikal Trimm suggests Hollywood stars, James P. Hogan protests: where is the plural in “stars” coming from? We are in Texas! Paul Benjamin argues that plural is allowed, because “The stars at night are big and bright” in Texas. Someone suggests that each proposition gets extra points if it can be sung. (That didn’t happen. There was no point system.)
The editor reminds everybody it’s time to move on.
James Hogan. Our planet is American football-shaped. The atmosphere is concentrated in the middle. It gets thinner towards the end. As you walk toward the poles, you are ascending through the atmosphere. The tip of the planet moves in the synchronous speed, so you can step off it and be in orbit. (See explanation at the bottom — E.) As a result, we were building wooden spaceships before we built boats. We got the timber to the north pole, and we built an ark like Noah. We have lots of time to kill and we can admire the universe without atmosphere and all those restrictions of ground-based forms of life. And all the spiritual and intellectual development that comes with it.
Elizabeth Moon. I would like to migrate to his (Hogan’s) planet!
She moves to the left of James Hogan. And Julie Czerneda moves towards Paul Benjamin and MT. Suddenly out of 3 universes there are only 2 left.
A guy from the audience. Does your planet rotate along the long axis, or the short?
Hogan. Along the long axis.
Editor. It would precess. It’s physically unstable.
Moon. It would precess. So what?
Here comes the inevitable kitchen sink
Paul Benjamin. Now it’s time to talk about the kitchen sink.
The guy named David from the audience. An important point is, on the football shaped world, which direction does the water go when it goes down the kitchen sink?
Hogan. On our planet we have two kitchen sinks. One kitchen sink has a large hole, and you can mix drinks over it. The other kitchen sink is when people had too much to drink, and multiple people can lean over it at the same time.
Benjamin. In the Dyson sphere you would have elevators in the buildings, but they would go to the center and away from the buildings, so you would get lighter as they went further… When you’re on the equator and you’re taking an elevator, the gravity would get lighter if you go further, or if you go closer to the pole.
A meteor struck a hole in the Dyson sphere, and made a mountain, and it has the most expensive property, because it has the best views.
Hogan. Except to climb the mountain you are going downhill.
Well, I found out what James P. Hogan meant about stepping off the planet into geosynchronous orbit. The geosynchronous orbit would have to be located at, or a very short distance above, the planet’s surface. That way the inhabitants of that planet could “step off” the planet (I prefer to say “jump up”) and find themselves in orbit.
A certain physics major finally explained it to me with diagrams, which I include below. It turned out this notion isn’t as magic as I thought it was. It’s no less fascinating, it’s just that it follows from very simple laws of physics I should have learned in high school.
And the planet does not even have to be shaped like an American football, like James P. Hogan suggested. It can be a sphere. But I’m getting ahead of myself.
If you are in a geosynchronous orbit, you stay above the same point of the planet at all times, because you are rotating along with the planet. This can only happen if the forces acting on you in opposite directions cancel each other out. The forces acting on you in the orbit are the centrifugal force, caused by the planet’s rotation, which pushes you away from the planet, and gravity, which pulls you towards the planet. A geosynchronous orbit is an orbit where these two opposite forces are equal. It can only occur above the equator, and only at a certain distance from the center of the planet. We need to find that distance.
Gravity (FG in the equation below) is equal to GN M m / a 2 , where GN is Newton’s gravitational constant, M is the mass of the planet, m is the mass of the person trying to launch himself into orbit, a is the distance from the center of the planet to the geosynchronous orbit.
On the other hand, a planet shaped like an American football… Actually, I hate this term. I’m not interested in any sports, including football, and I would like to use a more elegant, scientific term. I think ellipsoid will be a good enough approximation. So, an ellipsoid-shaped planet has two radii, a longer one and a shorter one, so this gives us more leeway regarding the planet’s size. Imagine that the ellipsoid is rotating around its vertical axis, kind of like if you put an egg on its side and spin it to test if it’s hard-boiled. In that case the geosynchronous orbit will occur along the “longer” equator. If the a in this formula is the longer radius — the distance from the ellipsoid’s center to one of the poles — then you would be able to launch yourself into a geosynchronous orbit by jumping up a little bit at the pole.
It is easier to find an ellipsoidal planet with just the right mass and the right longer radius than it is to find a sphere, because the formula says nothing about the shorter radius. If the shorter radius is very short, then the planet does not have to be very big. So maybe that’s why James P. Hogan suggested that his planet is ellipsoidal.